Thermoelectric materials can convert waste heat into usable power and thus have great potential as an energy technology. However, the thermoelectric efficiency of a material is quantified by its figure of merit, which has historically remained stubbornly low. One possible avenue towards increasing the figure of merit is through the use of low-dimensional nanograined materials. In such a system ...

We present density functional theory (DFT) based non-equilibrium Green’s function (NEGF) calculations for the conductance through a nitrobenzene molecule, which is anchored by pyridil-groups to Au electrodes. This work is building up on earlier theoretical studies where quantum interference effects have been identified both in qualitative tight-binding (TB) and in DFT descriptions for the same ...

The dimensions of electronic devices are rapidly decreasing and there is a need for a new generation of modeling tools that can accurately calculate the electrical properties of devices where atomic scale details and quantum effects are important. A promising framework for such calculations is density functional theory within the non-equilibrium Green's function formalism (NEGF-DFT). In this pa...

Semiconductor nanowires are possible candidates to replace the metal-oxide-semiconductor field-effect transistors (MOSFET) since they can act both as active devices or as device connectors. In this article, the transmission coefficients of Si and GaAs nanowires with arbitrary transport directions and cross sections are simulated in the nearestneighbor sp3d5s∗ semi-empirical tight-binding method...

Carbon-based materials such as carbon nanotubes (CNTs) and Graphene nano-ribbons (GNRs) have been extensively studied in recent years due to their exceptional electronic, opto-electronic, and mechanical properties. We employed the non-equilibrium Green’s function (NEGF) formalism to analyze the electronic and optoelectronic properties of CNTand GNRbased devices numerically. The steady-state and...

Single-molecule scanning tunneling spectroscopy (STS), with dephasing due to elastic and inelastic scattering, is of some current interest. Motivated by this, we report an extended Hückel theory (EHT)-based mean-field non-equilibrium Green’s function (NEGF) transport model with electron–phonon scattering treated within the self-consistent Born approximation (SCBA). Furthermore, a procedure base...

We perform density functional theory (DFT) calculations on molecular junctions consisting of a single molecule between two Au(111) electrodes. The molecules consist of an alkane or aryl bridge connecting acceptor, donor or thiol endgroups in various combinations. The molecular geometries are optimized and wavefunctions and eigenstates of the junction calculated using the DFT method, and then th...

Spin-dependent quantum transport properties in twisted carbon nanotube and stretched carbon nanotube are calculated using density functional theory (DFT) and non-equilibrium green’s function (NEGF) formulation. Twisting and stretching have no effect on spin transport in CNTs at low bias voltages. However, at high bias voltages the effects are significant. Stretching restricts any spin-up curren...

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In this article, a new structure is presented for MOS (Metal Oxide Semiconductor)-like junctionless carbon nanotube field effect transistor (MOS-like J-CNTFET), in which dual material gate with different work-functions are used. In the aforementioned structure, the size of the gates near the source and the drain are 14 and 6 nm, respectively, and the work-functions are equal and 0.5 eV less tha...